Rock bit



Feb. V28,l 1950 w. A. ROBERTS lROCK BIT Filed July 1l, 1946 FIGURE 2 I I N VEN TOR.

WILLIAM A. ROBERTS Patented Feb. 28, 1950 UNITED sTATEs vPATENT OFFICE RGCK BIT William A. Roberts, Lakewood, Colo.

Application July 11, 1946, Serial No. 682,889

This invention relates to an improved rock drill bit which is especially adapted to cut and break small rock that falls down the hole behind the bit during the drilling operation.

An object of the invention is to provide a drill bit having cutting edges on the top surface thereof which will cut rocks that fall on the top of the bit and jam the bit in the hole, sometimes making it impossible to loose the bit from the hole.

The present type of bits that are being used do not provide means for cutting the falling rocks and it requires extra labor, material and expense to remove such bits from the hole when jammed. However, the present bit, which is provided with cutting edges on the top surfaces of the cutters, will cut this fallen rock and aid in removing the bit from the hole.

With the above and other objects and advantages in view, the invention consists of the novel details of construction, arrangement and combination of parts more fully hereinafter described, claimed and illustrated in the accompanying drawing in which:

Figure 1 is a perspective view of anfembodiment of the invention, and

Figure 2 is a vertical, longitudinal sectional view thereof.

Referring more in detail to the drawing, the reference numeral I designates the drill which is constructed in accordance with the invention.

The bit comprises the tubular shank I2 which is internally threaded with left-hand round threads I4.

The shank is provided with the inclined oppositely positioned downwardly inclined ribs I6 having concave sides I8 and the upwardly tapered cutting edges 20.

The ribs I6 have nat upper surfaces 22, and these surfaces are provided with upwardly inclined reverse cutting blades 24 having the knife edge 26 extending from a point adjacent the cutting edges 20 to a point above the ribs I6 where the blades terminate in the cutting edges 28 having the knife edge 30 and these edges are in reverse relation to the edges 20.

The edges 20 are provided at their central point with the water inlets 32, and these inlets form a center point 34 which is at the center vertical line of the bit. These openings communicate with the water passage 36 as do the 1 Claim. (Cl. Z55-64) openings 38 positioned in the shank I2 intermediate of the ribs I6, and the passage 36 communicates with the threaded bore of the shank.

It will be apparent from the foregoing description that a bit as above described will, with the use of the cutting blades 24 and edges 28, cut any rock falling on top of the bit, to permit easy removal of the bit as directed, thus Dreventing jamming of the bit and saving time in its removal.

It is believed that the construction and advantages of the invention will be apparent to those skilled in the art, and it is to be understood that changes in the minor details of construction, arrangement and combination of partsmay be resorted to, provided they fall within the spirit of the invention and the scope of the appended claim.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

In a bit of the character described having an internally threaded tubular shank, the improvement comprising ribs on said shank in diametrically opposed relation to each other, said ribs having downwardly and outwardly inclined outer faces and concave sides, upwardly and outwardlyl REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,718,462 Hardsocg June 25, 1929 2,101,566 Vanderpool Dec. 7, 1937 2,150,189 Ronneberg Mar. 14, 1939 

